Polysomnography test 1

Signal Pathway

Body, Electrode or Sensor, Headbox, Amplifier, Analog to digital processing, Recording Montage

Bioelectric Signals

Voltages generated from the body

Transduced Signals

voltages produced from sensors attached to the body

Voltage

measure of potential energy

Electric Current

the flow of electrons

Resistance

the opposition to the flow of electrons through material

Ohm’s Law

(I=V/R) the current flow is proportional to voltage and resistance

Differential Amplifier

produces the final output signal by eliminating background noise

Common Mode Rejection

eliminating unwanted voltages that are common to both electrodes

Polarity

the direction of the signal away from the baseline

Sampling Rate

how often the PSG system samples and converts data

Recording Montage

the channels and setting in a standard PSG

Calibration

the determination and documentation of the accuracy of a measurement or observation

Impedence Check

electronic stamp of electronic impedences in Ohms

Biocalibrations

exercises performed by the patient to verify correct sensor response

Artifact

undesirable signal appearing in a recording

Biopotential

electrical signal generated by physiological processes in the body

Two-Pass method

each record is reviewed at least twice, first to identify sleep stages, and second to identify clinical events

Sinusoidal Waves

have the shape of a sine curve

Alpha Waves

Frequency: 8-13 Hz

Theta Waves

Frequency: 4-7 Hz

Vertex Sharp Waves

Frequency: greater than or equal to 2 Hz (<0.5 seconds)

K-Complex

Frequency: <2 Hz (greater than or equal to 0.5 seconds)

Sleep Spindles

Frequency: 11-16 Hz

Slow Wave Activity (Delta Waves)

Frequency: 0.5-2 Hz

Sawtooth Waves

Frequency: 2-6 Hz

Slow Eye Movements (SEM)

conjugate, regular, sinusoidal, >500 ms

Conjugate

coupled or paired

Rapid Eye Movements (REM)

conjugate, irregular, sharply peaked, <500 ms

Stage N1

EEG: Theta, Vertex Sharp Waves

Eyes: Slowly rolling eyes

Chin Movement: Remains elevated

Stage N2

EEG: Background theta waves, sleep spindles and k-complexes

Eyes: no eye movement

Chin Movement: decreased from baseline

Stage N3

EEG: slow wave activity (delta waves)

Eyes: no eye movement

Chin Movement: decreased from baseline

Stage REM

EEG: background theta waves, sawtooth waves (not required)

Eyes: rapid eye movements

Chin Movement: no chin activity

Obstructive Apneas

no airflow (90%)

continued effort

10 seconds

Central Apneas

No airflow

No effort

10 seconds

Mixed Apneas

No airflow

Mixed Effort

10 seconds

Hypopneas

Reduced Airflow (30%)

Continued Effort

10 seconds

Q30 documentation

structured technologist note every 30 minutes

System Referencing

all EEG electrodes are referencing to one system electrode

Derivation

the combination of exploring electrode and reference electrode

Re-referencing

utilizing the alternate reference electrode when one becomes dislodged

Amplifier Filters

isolate and record specific frequencies while eliminating undesirable signal information

High Frequency Filter

eliminates unwanted high frequencies

Low Frequency Filter

eliminated unwanted low frequency